As the switch device employed for such kind of use, a switch device disclosed in JP-A-2008-91212 is known. FIGS. 14 to 16 show an example of a seesaw type switch device disclosed in JP-A-2008-91212.
This switch device 170 includes a switch lever 171, a switch cover 172, a switch base 173 and a switch knob 174 and is attached to a functional part housing 175 and a design part cover 176 of an indoor lighting device for a vehicle. The switch base 173 is fixed to the functional part housing 175 and an operating part of the switch knob 174 is exposed outside from an opening 176a of the design part cover 176. The switch base 173 is connected to the switch cover 172 with the switch lever 171 accommodated therein.
The switch lever 171 and the switch knob 174 are attached so as to be freely swung on a supporting point 178 for swing. In a lower part of the switch lever 171, a through hole 171a is formed and a spring 171e is accommodated in the through hole 171a. In one end side of the spring 171e, an engaging ball 171f is arranged. In the other end side of the spring, a movable contact 171g is arranged. The engaging ball 171f is resiliently urged by the spring 171e. 
In the switch base 173, a rectangular tubular member 173b is provided. In one inner side surface of opposed inner side surfaces of the tubular member 173b, a plurality of vertical grooves 173d are formed. On the other inner side surface, fixed contacts 173e formed respectively with parts of bus bars are arranged. In this case, the fixed contacts 173e are arranged by setting plate surfaces of parts of the bus bars as a set of contact parts relative to the movable contact 171g. 
Then, under a state that the switch lever 171 is attached to the switch base 173, the engaging ball 171f slides on the inner side surface on which the vertical grooves 173d are formed and the movable contact 171g slides on the inner side surface on which the fixed contacts 173e are arranged. When the engaging ball 171f is fitted to the vertical groove 173d, the switch lever 171 is positioned at a prescribed position. Accordingly, in accordance with a switching operation of the switch lever 171 and the switch knob 174 to which a sense of moderation is given due to a positioning operation, a connection of the fixed contacts 173e and the movable contact 171g can be switched.
JP-A-2008-91212 is discussed in the above as background art.